Funnel–mantle locking apparatus
The funnel–mantle locking apparatus is a structure found in many cephalopods that connects the mantle and hyponome and restricts their movement relative to each other. It consists of two interlocking components: one located on the mantle and the other on the funnel. The apparatus may permit some anterior–posterior displacement or prevent movement altogether.
Variability
Funnel component
Six major forms of the funnel locking apparatus are recognised among teuthids and several more are found in the sepioids.| Shape of funnel locking apparatus | Species | Family |
| Idioteuthis cordiformis | Mastigoteuthidae | |
| Magnapinna talismani | Magnapinnidae | |
| Mastigoteuthis flammea | Mastigoteuthidae | |
| Mastigoteuthis glaukopis | Mastigoteuthidae | |
| Mastigoteuthis grimaldii | Mastigoteuthidae | |
| Mastigoteuthis magna | Mastigoteuthidae |